Chatham Dockyard workers took part in a rehearsal of passive defence against air attack to-day. It was assumed that the dockyard was raided by a force of enemy aeroplanes. At 9 a.m. the warning was given by telephone from Admiralty House and 10 minutes later the sirens gave the alarm to the 11,000 men working in the naval establishment.

At 33 points over the 500-acre dockyard the dropping of bombs was simulated and several buildings were theoretically blown up and roads made impassable. The raid lasted 10 minutes. As soon as the “raiders passed” Signal was given 500 passive defence workers – firemen, decontamination squads, first-aid and working parties – came into action. Parties of men wearing gas-masks and protective clothing cleared up gas from buildings and roads, firemen dealt with two fires, caused by incendiary bombs, and first-aid parties rescued 125 casualties from demolished premises. It was assumed that several important telephone lines had been severed. Up to the moment of the raid the workers in the precaution services had been unaware of the location of the hits.

The exercise was supervised by Rear Admiral C.F.S. Danby, Admiral Superintendent, and was organized by Commander H.C. Woolrych, R.N., retired, passive air defence officer for the dockyard. A test last October showed that the entire dockyard personnel can reach cover within 5 minutes. A further test of both mobile and passive defence organizations will be made.